Vessel having a compartment for containing water

ABSTRACT

A vessel has a compartment ( 34 ) for containing water, which compartment ( 34 ) has at least one opening ( 31 ) in a wall ( 30 ) thereof for allowing water to pass therethrough. The compartment ( 34 ) comprises an assembly ( 1 ) of a grating ( 10 ) and at least one anti-biofouling source ( 20 ), the grating ( 10 ) being positioned in the opening ( 31 ) for blocking items from passing through the opening ( 31 ) along with the water, and comprising a number of elements and spaces between the elements, and the anti-biofouling source ( 20 ) being configured to emit ultraviolet light during operation thereof for realizing anti-biofouling of at least a portion of the grating ( 10 ). At least one of the elements of the grating ( 10 ) is at least partially transparent to the ultraviolet light, enabling a design of the assembly ( 1 ) in which anti-biofouling of the entire grating ( 10 ) may be guaranteed.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This application is the U.S. National Phase application under 35 U.S.C.§ 371 of International Application No. PCT/EP2016/075001, filed on 19Oct. 2016, which claims the benefit of European Patent Application No.15191866.1, filed on 28 Oct. 2015. These applications are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The invention relates to a vessel having a compartment for containingwater, which compartment is delimited by a portion of the vessel's hulland an interior wall arrangement of the vessel connecting to the hull,and which compartment has at least one opening in a wall thereof forallowing water to pass therethrough, wherein the compartment comprises agrating which is positioned in the opening for blocking items frompassing through the opening along with the water, and which comprises anumber of elements and spaces between the elements.

BACKGROUND OF THE INVENTION

In many practical cases, a ship, which is a practical embodiment of avessel, has one or more compartments for containing water, which arepartially delimited by the ship's hull, wherein the hull is providedwith one or more openings at the position of each of the compartmentsfor allowing exchange of water between the compartments and the ship'senvironment. Such compartments, which are often referred to as seachests, may be used for taking in water to be used as ballast water orfire extinguishing water, for example. According to another possibility,assuming that the ship is of the engine-driven type, one or more seachests may be used for accommodating a so-called box cooler for coolingthe fluid of an engine cooling system of the ship, in which case theship's hull is provided with openings for enabling a continuous flow ofwater through the sea chests and thereby achieving an effective coolingeffect as desired. Usually, a box cooler as may be present in a seachest comprises a plurality of tubes for containing and transporting thefluid to be cooled in their interior, wherein entry and exit openingsare arranged in the hull at the position of the sea chest so that watercan enter the sea chest, flow over the tubes in the sea chest, and exitthe sea chest through natural flow and/or under the influence of motionof the ship.

In order to allow a sufficient flow of water through an opening of a seachest on the one hand and to prevent items (including marine animals)which are small enough to pass through the opening from entering the seachest on the other hand, it is practical for the opening to be equippedwith a grating. As is generally known, a grating comprises one or moreelements which are suitable for serving as a barrier extending in anopening. Normally, such elements have an elongated shape. In case agrating comprises a plurality of elements, the elements are oftenpositioned in a regularly spaced arrangement. Basically, a gratingcomprising a plurality of elements may comprise a single set of theelements, wherein the elements are arranged in parallel, extending in acertain direction. However, it is also possible for a grating comprisinga plurality of elements to comprise two sets of parallel elements,wherein the elements of the two sets extend in perpendicular directions.In any case, the size of the spaces between adjacent elements of agrating determines the size of items to be blocked by the grating.

Especially in case a grating is used in a marine environment, it mayhappen that the grating gets clogged as time passes, which hinders theflow of water through the opening in which the grating is present, andwhich may eventually result in total blockage of the opening. Suchclogging is caused by a well-known phenomenon called biological foulingor biofouling.

In general, biofouling is the accumulation of microorganisms, plants,algae, small animals and the like on surfaces. According to someestimates, over 1,800 species comprising over 4,000 organisms areresponsible for biofouling. Hence, biofouling is caused by a widevariety of organisms, and involves much more than an attachment ofbarnacles and seaweeds to surfaces. Biofouling is divided into microbiofouling which includes biofilm formation and bacterial adhesion, andmacro biofouling which includes the attachment of larger organisms. Dueto the distinct chemistry and biology that determine what prevents themfrom settling, organisms are also classified as being hard or soft. Hardbiofouling organisms include calcareous organisms such as barnacles,encrusting bryozoans, mollusks, polychaetes and other tube worms, andzebra mussels. Soft biofouling organisms include non-calcareousorganisms such as seaweed, hydroids, algae and biofilm “slime”.Together, these organisms form a biofouling community.

In several situations, biofouling creates substantial problems.Biofouling can cause machinery to stop working, water inlets to getclogged, and heat exchangers to suffer from reduced performance. Hence,the topic of anti-biofouling, i.e. the process of removing or preventingbiofouling, is well-known. In industrial processes involving wettedsurfaces, bio dispersants can be used to control biofouling. In lesscontrolled environments, biofouling organisms are killed or repelledwith coatings using biocides, thermal treatments or pulses of energy.Nontoxic mechanical strategies that prevent organisms from attaching toa surface include choosing a material or coating for causing the surfaceto be slippery, or creating nanoscale surface topologies similar to theskin of sharks and dolphins which only offer poor anchor points. As analternative, ultraviolet light may be used for removing/preventing theformation of biofilm on wet surfaces. For example, WO 2014/014779discloses a system for reducing biofouling of a surface of an opticallytransparent element subjected to a marine environment, including an LEDfor emitting ultraviolet radiation, a mount for directing emittedultraviolet radiation toward the optically transparent element, andcontrol circuitry for driving the LED.

U.S. Pat. No. 5,308,505 discloses an anti-biofouling system for use witha grating. During operation of the anti-biofouling system, the gratingis illuminated with ultraviolet light for the purpose of keeping thegrating holes and the grating surface free from biofouling.

SUMMARY OF THE INVENTION

It is an object of the invention to provide anti-biofouling measureswhich are applicable to a grating used in an opening of a vessel'scompartment, which are effective yet considerably less harmful to theenvironment than some of the known measures, and which have relativelyuncomplicated constructions or are not so much susceptible to damage.According to the invention, a vessel having a compartment as defined inthe opening paragraph, which compartment comprises a grating asmentioned, comprises an assembly of the grating and at least oneanti-biofouling source, wherein the anti-biofouling source is configuredto emit ultraviolet light during operation thereof for realizinganti-biofouling of at least a portion of the grating, and wherein atleast one of the elements of the grating is at least partiallytransparent to the ultraviolet light.

In the context of the invention, anti-biofouling of at least a portionof the grating is realized on the basis of applying at least oneanti-biofouling source which is configured to emit ultraviolet lightduring operation thereof, and which may comprise at least one lightsource such as an LED, for example. The grating is adapted to allow theultraviolet light to pass through at least a portion of the elementsthereof, wherein at least one of the elements of the grating is at leastpartially transparent to the ultraviolet light, on the basis of whichseveral advantageous options are obtained in respect of the positioningof the at least one anti-biofouling source with respect to the grating,as will be explained in the following. In any case, by having a gratingwhich at least partially does not block a transfer of the ultravioletlight, the anti-biofouling effects obtained by operating theanti-biofouling source are enhanced with respect to a situation in whicha conventional grating is used. In particular, by having an appropriatedesign of the grating, wherein at least portions of the grating atstrategic positions are transparent for allowing the ultraviolet lightto pass through the grating at those portions, it is possible to reachmore portions of the grating than as would be the case with anon-transparent grating, without needing to apply more anti-biofoulingsources. In other words, according to the invention, the at least oneanti-biofouling source can be applied for keeping the grating clean in amore efficient manner, not by modifying the anti-biofouling source insome way and/or increasing the number of anti-biofouling sources, but byadapting the design of the grating.

A well-known example of a vessel is a ship, and a well-known example ofa compartment which is positioned directly adjacent the ship's hull is aso-called sea chest as mentioned in the foregoing. It is noted that inthe context of the invention, the term “compartment” should preferablybe understood such as to at least cover any area, space, chamber orbasin which is at least partially delimited by a wall in which anopening is arranged for allowing water to pass therethrough, from thecompartment to outside of the compartment, and/or in the oppositedirection, whatever the case may be.

For the sake of clarity, it is noted that the word “grating” as used inthis text should be understood such as to be applicable to the materialappearance of the grating, i.e. the actual construction of the gratingwith the elements of the grating, rather than being applicable to theconcept of a grating in a more general sense, which also includes thespaces as present between the elements of the grating. Thus, when thegrating is said to be at least partially transparent to the ultravioletlight, or when a similar formulation is used, this should be understoodsuch as to mean that the entire construction of actual elementsconstituting the grating is at least partially transparent, whichimplies that at least part of the material as present in the grating istransparent. Also, this means that at the level of the elements, it maybe so that some or all of the construction elements are at leastpartially transparent, in conformity with what is mentioned earlier.

In a practical embodiment, the grating comprises a carrier frame andportions which are transparent to the ultraviolet light, the transparentportions being distributed over the carrier frame. The carrier frame cancomprise material which is not transparent to the ultraviolet light, andcan be made of metal, for example, or any other type of material whichis commonly used in the field of gratings. By having a combination ofmaterials in the grating, it is possible to realize a partiallytransparent character of the grating without necessarily decreasingconstructional strength of the grating, while a possible increase ofcosts of the grating can be kept to a minimum. Advantageously, thetransparent portions are distributed over the carrier frame, so as tohave both the effect of ultraviolet light being allowed to pass throughand the necessary constructional strength throughout the grating.Materials which are suitable for use in the transparent portions includequartz, silicones and calcium fluoride. It may particularly beadvantageous for the transparent portions to be transparent toultraviolet light having a wavelength in a range of 250 nm to 300 nm.

On the basis of the transparent character of at least a portion of thegrating, it is possible for the anti-biofouling source to be integratedin the grating and still be capable of performing its anti-biofoulingfunction on at least a portion of the grating. The fact is that theultraviolet light is allowed to pass through the grating at the areaswhere the grating is transparent. In a conventional situation, theultraviolet light would not be allowed to travel far through thegrating, as the ultraviolet light would be blocked by elements of thegrating. Hence, in such a situation, especially when the gratingcomprises two sets of parallel elements, wherein the elements of the twosets extend in perpendicular directions, integrating the anti-biofoulingsource in the grating would not help much in realizing anti-biofoulingof the grating, unless an anti-biofouling source would be arranged inevery mesh opening of the grating, which is expensive and not practical.Contrariwise, the invention offers a cost-effective and practicalsolution, wherein the number of anti-biofouling sources to be appliedwith the grating can be kept to a minimum, and wherein it is notnecessary to have one or more anti-biofouling sources at a positionoutside of the grating, which is advantageous when it comes toprotecting the anti-biofouling sources from getting damaged.

The number of anti-biofouling sources to be used with the grating can bechosen freely according to desire. The number of anti-biofouling sourcescan range from one anti-biofouling source to a plurality ofanti-biofouling sources, all of which can be integrated in the grating.

According to an option which may be applied as an alternative of theoption of integrating one or more anti-biofouling sources in thegrating, or as an addition to that option, at least one anti-biofoulingsource of the assembly can be positioned inside the compartment. In suchcase, it is possible for the at least one anti-biofouling source whichis positioned inside the compartment to be associated with a wall of thecompartment, for example.

In case the grating comprises a carrier frame and transparent portionsdistributed over the carrier frame, it is very practical for theanti-biofouling source to be integrated in the carrier frame. Also insuch case, the number of anti-biofouling sources to be used with thegrating may range from one anti-biofouling source to a plurality ofanti-biofouling sources.

For the sake of completeness, the following is noted in respect ofanti-biofouling by using ultraviolet light. The anti-biofouling sourcefor producing the ultraviolet light may comprise a light source which ischosen to specifically emit ultraviolet light of the c type, which isalso known as UVC light, and even more specifically, light with awavelength roughly between 250 nm and 300 nm. It has been found thatmost biofouling organisms are killed, rendered inactive, or renderedunable to reproduce by exposing them to a certain dose of theultraviolet light. A typical intensity which appears to be suitable forrealizing anti-biofouling is 10 mW per square meter, to be appliedcontinuously or at a suitable frequency. A very efficient source forproducing UVC light is a low pressure mercury discharge lamp, in whichan average of 35% of input power is converted to UVC power. Anotheruseful type of lamp is a medium pressure mercury discharge lamp. Thelamp may be equipped with an envelope of special glass for filtering outozone-forming radiation. Furthermore, a dimmer may be used with the lampif so desired. Other types of useful UVC lamps are dielectric barrierdischarge lamps, which are known for providing very powerful ultravioletlight at various wavelengths and at high electrical-to-optical powerefficiencies, and LEDs. In respect of the LEDs, it is noted that theycan generally be included in relatively small packages and consume lesspower than other types of light sources. LEDs can be manufactured toemit (ultraviolet) light of various desired wavelengths, and theiroperating parameters, most notably the output power, can be controlledto a high degree.

The light sources for emitting ultraviolet light can be provided in theform of a tubular lamp, more or less comparable to a well-known TL (tubeluminescent/fluorescent) lamp. For various known germicidal tubular UVClamps, the electrical and mechanical properties are comparable to thoseproperties of tubular lamps for producing visible light. This allows theUVC lamps to be operated in the same way as the well-known lamps,wherein an electronic or magnetic ballast/starter circuit may be used,for example.

A general advantage of using ultraviolet light for realizinganti-biofouling is that the microorganisms are prevented from adheringand rooting on a surface to be kept clean. Contrariwise, when knownpoison dispersing coatings are applied, the anti-biofouling effect isachieved by killing the microorganisms after they have adhered androoted on the surface. Prevention of biofouling by means of lighttreatment is preferred over removal of biofouling by means of lighttreatment, as the latter requires more input power and involves a higherrisk that the light treatment is not sufficiently effective. In view ofthe fact that the light sources for producing ultraviolet light may bearranged and configured such that only a relatively low level of inputpower is needed, the light sources may be operated to continuouslyproduce anti-biofouling light across a large surface without extremepower requirements, or the light sources may be operated at a dutycycle, wherein the light sources are on for a certain percentage of atime interval, and off for the rest of the time interval, wherein thetime interval may be chosen to be in the order of magnitude of minutes,hours, or whatever is appropriate in a given situation. As not muchadditional power is required, the light sources can be easily applied inexisting structures.

When the invention is applied, at least one ultraviolet light source isused for realizing anti-biofouling of a grating which is at leastpartially transparent to the ultraviolet light emitted by the lightsource during operation thereof. The light source may be arranged at anysuitable position with respect to the grating, which position may beoutside of the grating or integrated in the grating. In case at leasttwo light sources are used, all light sources may be positioned outsideof the grating, all light sources may be integrated in the grating, orone portion of the light sources may be positioned outside of thegrating whereas the other portion of the light sources may be integratedin the grating. An advantage of integrating a light source in thegrating is that in comparison with having a light source outside of thegrating, the risk of the light source getting damaged is relatively low.

The above-described and other aspects of the invention will be apparentfrom and elucidated with reference to the following detailed descriptionof two embodiments of an assembly for use with an opening of a ship'shull, comprising a grating and at least one anti-biofouling source foremitting ultraviolet light during operation thereof for realizinganti-biofouling of at least a portion of the grating. The embodimentsare just two examples of numerous possible embodiments existing withinthe framework of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in greater detail with reference tothe figures, in which equal or similar parts are indicated by the samereference signs, and in which:

FIGS. 1 to 3 relate to an assembly of a grating and at least oneanti-biofouling source according to a first embodiment of the inventionin which the at least one anti-biofouling source is arranged outside ofthe grating, the figures showing the assembly as used with an opening ofa ship's hull, wherein FIG. 1 diagrammatically shows a front view of thegrating, FIG. 2 diagrammatically shows a side view of the assembly and acompartment of the ship as partially delimited by the ship's hull, andFIG. 3 diagrammatically shows a side view of a portion of the grating;

FIG. 4 illustrates examples of the way in which rays of ultravioletlight emitted by the anti-biofouling source during operation thereof maytravel through an element of the grating; and

FIG. 5 relates to an assembly of a grating and at least oneanti-biofouling source according to a second embodiment of the inventionin which a plurality of anti-biofouling sources are integrated in thegrating, wherein the figure diagrammatically shows a side view of aportion of the assembly.

The figures are of a diagrammatical nature only and are not drawn toscale. For example, in FIG. 2, for the sake of illustrating the assemblyaccording to the invention, the assembly is depicted on a relativelylarge scale whereas the compartment is depicted on a relatively smallscale.

DETAILED DESCRIPTION OF EMBODIMENTS

FIGS. 1 to 3 relate to an assembly 1 of a grating 10 and at least oneanti-biofouling source 20 according to a first embodiment of theinvention in which the at least one anti-biofouling source 20 isarranged outside of the grating 10, the figures showing the assembly 1as used with an opening 31 of a ship's hull 30, wherein the grating 10is arranged in the opening 31 so as to block items from passing throughthe opening 31.

In general, an opening 31 in a ship's hull 30 has a function in allowingexchange of water between the immediate environment 32 of the ship and acompartment of the ship as delimited by a portion of the ship's hull 30and an interior wall arrangement 33 of the ship connecting to the hull30, which is shown in FIG. 2, and which will hereinafter be denoted assea chest 34. For example, the sea chest 34 may be used as a compartmentfor taking in water to be used as fire extinguishing water, or as acompartment for accommodating a box cooler which is enabled to performits cooling function by continuous exposure to fresh water from theship's environment 32 during operation. In order to prevent items suchas fishes and other marine animals, algae, waste floating in the wateretc. from entering the sea chest 34 along with an incoming flow ofwater, it is commonly known to provide a grating 10 and fit the grating10 in every opening 31 providing access to the sea chest 34.

Usually, a grating 10 comprises at least one element which is arrangedsuch as to be capable of serving as a barrier in the opening 31 in whichthe grating 10 is fitted. In fact, a grating 10 is adapted to divide anopening 31 in at least two openings of smaller size. In the shownexample, the grating 10 comprises a plurality of elements 11 having anelongated shape and extending substantially parallel with respect toeach other, in a regularly spaced arrangement. However, that does notalter the fact that the invention is equally applicable to any otherpossible type of grating, including the type comprising two sets ofsubstantially parallel elements, wherein the elements of the two setsextend in perpendicular directions. Also, it is noted that in manypractical cases, including the case as illustrated in FIG. 1, thegrating 10 comprises elements which are arranged such as to form aperipheral rim 41 of the grating 10. Advantageously, as shown in FIG. 2,the grating 10 comprises a hinge 12, so that the grating 10 may be putto a tilted position for purposes of cleaning and/or maintenance, forexample. The use of a hinge 12 with a grating 10 for openings 31 in aship's hull 30 is well known, and will not be further explained here.For obvious reasons, the hinge 12 is present at the side of the grating10 facing the sea chest 34, which will hereinafter be referred to asinterior side 13.

Spaces 14 between two adjacent elements 11 of the grating 10 arerelatively small, so that the grating 10 is effective in allowing onlywater to enter the sea chest 34 from the outside, while preventingobjects as may be present in the water to enter the sea chest 34 aswell. However, on the basis of this fact, there is a considerable riskof clogging of the grating 10, especially under the influence ofbiofouling. In order to significantly reduce this risk, at least oneanti-biofouling source 20 is provided, which serves for emittingultraviolet light during operation thereof, whereby it is possible torealize anti-biofouling of at least a portion of the grating 10. Theultraviolet light may be of the type known as UVC light, which is knownto be effective for realizing anti-biofouling of surfaces. Theanti-biofouling source 20 may be operated continuously, but it alsopossible to operate the anti-biofouling source 20 at certain intervalsonly, wherein the ultraviolet light may be dosed at a suitableintensity. The assembly 1 according to the first embodiment of theinvention comprises at least one anti-biofouling source 20 which isarranged outside of the grating 10, at a position for covering at leasta considerable portion of the grating 10 by the ultraviolet light to beemitted during operation. In the shown example, the anti-biofoulingsource 20 has an elongated tubular shape and is arranged inside the seachest 34 at a certain distance with respect to the grating 10, extendingsubstantially parallel to the grating 10, in a direction which issubstantially perpendicular to a direction in which the elements 11 ofthe grating 10 extend. Any suitable type of construction may be used forfixing the anti-biofouling source 20 at the appropriate position insidethe sea chest 34.

In view of the fact that the anti-biofouling source 20 is arrangedinside the sea chest 34, the interior side 13 of the grating 10 facingthe sea chest 34 is under the direct influence of the anti-biofoulingsource 20. Hence, the anti-biofouling effect on this side of the grating10 would be much stronger than on the other side of the grating 10,which will hereinafter be referred to as exterior side 15, if it wouldnot be for measures according to the invention, which involve designingthe grating 10 in such a way as to be at least partially transparent tothe ultraviolet light. In this way, a situation in which the grating 10clogs at the exterior side 15 thereof is prevented without a need forarranging another anti-biofouling source 20 at that side of the grating10, which would cause additional friction of movement of the ship andwhich would be very vulnerable to mechanical impact.

In the first embodiment of the assembly 1 according to the invention,the elements 11 of the grating 10 are partially transparent andpartially non-transparent. FIG. 3 illustrates the fact that the elements11 comprise a combination of a transparent portion 16 and anon-transparent portion 17. The non-transparent portions 17 of theelements 11 may be made of a relatively strong material such as steel inorder to serve as enforcement of the grating 10. Thus, the grating 10may comprise a carrier frame 40 which is composed of the non-transparentportions 17 of the elements 11 and the elements forming the peripheralrim 41 of the grating 10. In the shown example, the arrangement oftransparent portions 16 and non-transparent portions 17 is chosen suchas to have an optimum of constructional strength and permeability toultraviolet light. In particular, the non-transparent portions 17 arepresent at the interior side 13 of the grating 10, and extend in thedirection of the exterior side 15 along only a portion of the distancebetween the two sides 13, 15 of the grating 10, while being embedded inthe transparent portions 16.

In the assembly 1 according to the first embodiment of the invention,anti-biofouling of the grating 10 is realized by operating theanti-biofouling source 20 arranged inside the sea chest 34 so as to emitultraviolet light towards the interior side 13 of the grating 10. In thegrating 10, the ultraviolet light is passed on all the way to theexterior side 15 of the grating 10 through the transparent portions 16of the elements 11 of the grating 10. In this way, anti-biofouling ofthe entire grating 10 is realized, so that the capability of the opening31 in which the grating 10 is present to allow water to enter and/or toexit the sea chest 34 is preserved. Examples of the way in which theultraviolet light may travel through an element 11 at a position wherethe element 11 comprises a combination of a transparent portion 16 and anon-transparent portion 17 are shown in FIG. 4, the rays being depictedlike arrows. Especially, in FIG. 4, a cross-sectional view of theelement 11 is shown, so that it may be clear that some of the lightfollows such a path that the non-transparent portion 17 is notencountered, and that some of the light does encounter thenon-transparent portion 17, but may reach the exterior side 15 of thegrating 10 anyway on the basis of reflection on the non-transparentportion 17 and further travel through the transparent portion 16.

Like the assembly 1 according to the first embodiment of the invention,the assembly 2 according to the second embodiment of the inventioncomprises a grating 10 and at least one anti-biofouling source 20. Adifference between the two embodiments resides in the fact that in thesecond embodiment, the at least one anti-biofouling source 20 isintegrated in the grating 10. The second embodiment may still compriseone or more anti-biofouling sources 20 arranged outside of the grating10, but it is preferred for all anti-biofouling sources 20 of theassembly 2 to be integrated in the grating 10 in order to dispense witha need for measures aimed at realizing a stable positioning of theanti-biofouling sources 20 inside the sea chest 34. Also, theanti-biofouling sources 20 are very well protected against possibledamage in the case of the integrated arrangement of the anti-biofoulingsources 20 in the grating 10.

FIG. 5 illustrates how the integrated arrangement of the anti-biofoulingsources 20 in the grating 10 may be realized. In the shown example, theelements 11 of the grating 10 comprise transparent portions 16 andnon-transparent portions 17, wherein the non-transparent portions 17 arepositioned at the interior side 13 of the grating 10, and thetransparent portions 16 are positioned at the exterior side 15 of thegrating 10. Each of the non-transparent portions 17 is provided with anumber of recesses for accommodating anti-biofouling sources 20. Thenumber of recesses and the associated number of anti-biofouling sources20 per non-transparent portion 17 can be chosen freely within theframework of the invention. Also, it is not essential that everynon-transparent portion 17 is equipped with at least one anti-biofoulingsource 20, although this is preferred for obtaining optimalanti-biofouling results at a minimum of power consumption. Theanti-biofouling sources 20 may be provided in the form of LEDs foremitting ultraviolet light. It is practical for each of the elements 11of the grating 10 to be provided with arrays of LEDs, extending in thelongitudinal direction of the elements 11. In the shown example,complete coverage of the grating 10 for anti-biofouling purposes isobtained by having LEDs in the sides of the non-transparent portions 17of the elements 11 facing each other and the side of the non-transparentportions 17 facing the transparent portions 16. As is the case with thegrating 10 of the assembly 1 according to the first embodiment of theinvention, the grating 10 of the assembly 2 according to the secondembodiment of the invention can be sufficiently strong due to thepresence of the non-transparent portions 17 of the elements 11 thereof,constituting a carrier frame 40, and can also be effective in stayingclean under the influence of the ultraviolet light, the anti-biofoulingsources 20 being distributed over the carrier frame 40.

In a practical embodiment, the grating 10 of the assembly 1, 2 accordingto the invention may comprise a metal carrier frame 40 with silicones orTeflon. Possibly also sandwiches of silicon and quartz could be appliedin a way as known per se from the field of safety windows.

The invention is applicable to a ship as described in the foregoing, orto any other type of vessel, i.e. watercraft.

It will be clear to a person skilled in the art that the scope of theinvention is not limited to the examples discussed in the foregoing, butthat several amendments and modifications thereof are possible withoutdeviating from the scope of the invention as defined in the attachedclaims. It is intended that the invention be construed as including allsuch amendments and modifications insofar they come within the scope ofthe claims or the equivalents thereof. While the invention has beenillustrated and described in detail in the figures and the description,such illustration and description are to be considered illustrative orexemplary only, and not restrictive. The invention is not limited to thedisclosed embodiments. The drawings are schematic, wherein details thatare not required for understanding the invention may have been omitted,and not necessarily to scale.

Variations to the disclosed embodiments can be understood and effectedby a person skilled in the art in practicing the claimed invention, froma study of the figures, the description and the attached claims. In theclaims, the word “comprising” does not exclude other steps or elements,and the indefinite article “a” or “an” does not exclude a plurality. Anyreference signs in the claims should not be construed as limiting thescope of the invention. The phrase “a plurality of” as used in this textshould be understood such as to mean “at least two”.

Elements and aspects discussed for or in relation with a particularembodiment may be suitably combined with elements and aspects of otherembodiments, unless explicitly stated otherwise. Thus, the mere factthat certain measures are recited in mutually different dependent claimsdoes not indicate that a combination of these measures cannot be used toadvantage.

The term “substantially” as used in this text will be understood by aperson skilled in the art as being applicable to situations in which acertain effect is intended which can be fully realized in theory butwhich involves practical margins for its factual implementation.Examples of such an effect include a parallel arrangement of objects anda perpendicular arrangement of objects. Where applicable, the term“substantially” may be understood such as to be an adjective which isindicative of a percentage of 90% or higher, such as 95% or higher,especially 99% or higher, even more especially 99.5% or higher,including 100%.

The term “comprise” as used in this text will be understood by a personskilled in the art as covering the term “consist of”. Hence, the term“comprise” may in respect of an embodiment mean “consist of”, but may inanother embodiment mean “contain/include at least the defined speciesand optionally one or more other species”.

In view of the fact that biofouling does not only occur at sea, but alsoin rivers, lakes, basins and the like, the measures according to theinvention are generally applicable in a context in which an opening forallowing water to pass therethrough is present. Examples of such acontext include the context of marine objects such as oilrigs, or othertypes of buildings and constructions in or next to the ocean/sea, andthe context of water cooling systems of power plants. In fact, themeasures of the invention can be put to practice in every situation inwhich a grating is present and in which the grating is exposed to waterduring at least a part of its lifetime, such that the grating may sufferfrom biofouling as a consequence thereof.

Summarizing, a vessel has a compartment 34 for containing water, whichcompartment 34 is delimited by a portion of the vessel's hull 30 and aninterior wall arrangement 33 of the vessel connecting to the hull 30,and which compartment 34 has at least one opening 31 in a wall 30thereof for allowing water to pass therethrough. The compartment 34comprises an assembly 1, 2 of a grating 10 and at least oneanti-biofouling source 20, the grating 10 being positioned in theopening 31 for blocking items from passing through the opening 31 alongwith the water, and comprising a number of elements 11 and spaces 14between the elements 11, and the anti-biofouling source 20 beingconfigured to emit ultraviolet light during operation thereof forrealizing anti-biofouling of at least a portion of the grating 10. Atleast one of the elements 11 of the grating 10 is at least partiallytransparent to the ultraviolet light, enabling a design of the assembly1, 2 in which anti-biofouling of the entire grating 10 may beguaranteed, even in case the at least one anti-biofouling source 20 ispositioned at only one side 13 of the grating 10 and/or inside thegrating 10.

The invention claimed is:
 1. A vessel having a compartment forcontaining water, which compartment is delimited by a portion of thevessel's hull and an interior wall arrangement of the vessel connectingto the hull, and which compartment has at least one opening in a wallthereof for allowing water to pass therethrough, wherein the compartmentcomprises an assembly of a grating and at least one anti-biofoulingsource, the grating being positioned in the opening for blocking itemsfrom passing through the opening along with the water, and comprising anumber of elements and spaces between the elements, and theanti-biofouling source being configured to emit ultraviolet light duringoperation thereof for realizing anti-biofouling of at least a portion ofthe grating, and wherein at least one of the elements of the grating isat least partially transparent to the ultraviolet light.
 2. The vesselaccording to claim 1, wherein at least one anti-biofouling source of theassembly is integrated in the grating.
 3. The vessel according to claim1, wherein the assembly comprises a plurality of anti-biofouling sourceswhich are integrated in the grating.
 4. The vessel according to claim 1,wherein at least one anti-biofouling source of the assembly ispositioned inside the compartment.
 5. The vessel according to claim 4,wherein the at least one anti-biofouling source which is positionedinside the compartment is associated with a wall of the compartment. 6.The vessel according to claim 1, wherein the grating comprises a carrierframe and portions which are transparent to the ultraviolet light, thetransparent portions being distributed over the carrier frame.
 7. Thevessel according to claim 6, wherein at least one anti-biofouling sourceof the assembly is integrated in the carrier frame.
 8. The vesselaccording to claim 6, wherein the assembly comprises a plurality ofanti-biofouling sources which are integrated in the carrier frame. 9.The vessel according to claim 6, wherein the carrier frame of thegrating is made of a material which is non-transparent to theultraviolet light.
 10. The vessel according to claim 6, wherein thecarrier frame of the grating is made of metal.